Sustainable Development Strategy for Geothermal Resources in El Salvador

Abstract

LaGeo is developing guidelines to assess the sustainability of geothermal reservoirs utilization. A calibrated 3D numerical model will be necessary at the beginning. Considering technological aspects the forecast have been calculated for two periods of time, 50 and 100 years, assuming a sustainable mass extraction or energy production. The 3D model using TOUGH2 is coupled to the well bore simulator HOLA in order to predict the wellhead conditions for each well during the forecast periods. The results are put into a gathering system simulator to obtain the inlet pressure at the turbine. As a case the Ahuachapán field evaluation is presented. The field is now generating close to 85 MW with the three units and total mass extraction of 900 kg/s. Applying the methodology, the preliminary results indicates that planned power production can not be sustained more than 50 years due to the present power plant technology and the gathering system presently available, because some wells will not be able to sustain production or the wellhead pressure will be lower than the inlet pressure of the turbines. To sustain the exploitation for at least 100 years at least the following changes could be implemented: (1) Improve the gathering system using large diameter steam pipeline (high ways), (2) expand the exploitation area to the south-east and south-west and finally (3) reduce the inlet pressure of the turbine.